The present invention relates to timing circuits for an intermittent operating ink jet system printer of the charge amplitude controlling type.
In conventional mechanical printers, a head is transported by one character space and stopped at that position upon completion of one character printing. Printing is again effected upon receipt of the next printing information from a key. Thus, the head is stopped during the printing operation and as a result, the velocity of movements of the head in no way influence printing accuracy.
In contrast with the foregoing, in the ink jet system printer of the charge amplitude controlling type, vertical deflection is achieved by a pair of high voltage deflection plates and horizontal deflection is achieved by transporting the head at a fixed velocity in the horizontal direction. It is, therefore, quite essential that the head is transported at a substantially constant velocity for the printing process. More specifically, in the intermittent operating ink jet system printer of the charge amplitude controlling type, which makes a record on a writing medium in accordance with input signals intermittently introduced, for example, by means of a keyboard, the head, which has an ink issuing nozzle must start travelling upon receipt of the input signals and stop upon completion of one-character printing. The reason for this is that the input signals are introduced with no synchronization with the various control signals for the printer apparatus. Variations in the velocity of the head movements result in a considerably reduced printing accuracy. Needless to say, it is impossible to speed the head up from a stationary state to the desired velocity in a moment.
An object of the present invention is to provide a timing circuit which is useful for an intermittent operating ink jet system printer of the charge amplitude controlling type.
Another object of the present invention is to provide a circuit construction wherein after receiving intermittent input signals, the generation of the printing start signals is delayed for a period of time until the velocity of the head has stabilized.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Pursuant to the present invention, although the head starts travelling in response to intermittently introduced print information, printing is not carried out until the velocity of the head becomes stable, that is, printing is inhibited while the head velocity is in the transient state, that is, where the head velocity is continually varying.